Age-related Changes

Dr/ Rehab F. Gwada

Objectives of the lecture

At the end of this lecture the student will be able to:

Define the vitality with aging .

Distinguish between the age-related physiological changes and pathological changes of body systems.

Determine Age-related Changes in Musculoskeletal Cardiovascular, skin , and respiratory system .

ASPECTS OF AGING

• Two aspects of aging

Increase in vitality- birth to 30 years old (growth)

Decrease in vitality - 30 to death.(decline)

What is Vitality

• The ability to respond to stress, the amount of

reserve capacity

• The greater number of functioning cells per

organ the greater the ability to respond to stress

• Maximum vitality is 100%.

• Loss of vitality is 0.8% to 1% per year after age 30

Homeostasis

You

Compensatory Mechanisms

You, Compensated

Physiologic Reserve

stress

Frail Elderly

Compensatory Mechanisms Limited Blunted

“Tapped Out”

Clinically Decompensated

Physiologic Reserve

stress

Changes that are part of the normal aging process (successful aging -good genes and lifestyle) and experienced by everyone

Age Related Changes

Age Associated Diseases (pathological changes )

Changes caused by interaction of negative genes and a poor lifestyle leading to diseases that reduce independence resulting in possible dependent care

Cardiovascular Changes Related to Aging

• Deposits of the "aging pigment," lipofuscin, accumulate.

• The valves of the heart thicken and become stiffer.

• The number of pacemaker cells decrease and fatty & fibrous tissues increase about the SA node. These changes may result in a slightly slower heart rate. And increase the risk of atrial fibrillation

• A slight increase in the size of the heart, especially the left ventricle, is common. The heart wall thickens & Some myocytes are replaced by fibrous tissue.

• The enlarged left ventricular wall has a decreased ability to expand during diastole Results in reduced and delayed filling

Cardiovascular Changes Related to Aging

• The left ventricle contracts less and ejects less blood.

• There is an increase in left atrium size, secondary to the decline in left ventricle compliance.

• This increases the work load on the atria

.

Cont.

• Under normal circumstances, the heart continues to adequately supply all parts of the body. However, an aging heart may be slightly less able to tolerate increased workloads.

• Examples of stressors include: illness, infections, emotional stress, injuries, and extreme physical exertion.

Changes in the Vessels

• Arteries • thickening , stiffening & decrease in elasticity results in: • Increased peripheral resistance • Increased arterial pressure

• Veins • The ability of the vessel to contract is decreased. • Dilation and tortuosity of veins may results in decreased venous

return.

• Little research has been done on the aging veins

Heart Rate

• Resting heart rate (HR) does not change very much with age.

• The maximum exercise heart rate decreases with age.

• 200 beats/min at age 20

• 150 beats/min at age 70

• to calculate estimated maximum exercise heart rate:

Max HR= 220 –age(years)

The reason:

1- Alteration in SA node activity

2- Reduce beta-adrenergic sensitivity

.

Stoke volume &COP

• stroke volume (SV) is the volume of blood pumped from one ventricle( usually left ventricle) of the heart with each beat.

• Stroke volume is changed little by aging; at rest in healthy individuals, there may even be a slight increase.

• Cardiac output at rest is unaffected by age. Maximum

cardiac output and aerobic capacity are reduced with age. Due to decline in max HR and left ventricular ejection

• Max Cardiac Output = Stroke Volume X max HR

(ml/min) (ml/cycles) (cycles/min)

Blood Pressure

• Systolic BP tends to increase with age throughout life – 5-8 mm Hg per decade after 40-50 years of age – an index of arterial stiffness

• Diastolic BP tends to increase until the age of 60, then it stabilizes or slowly declines

Increases in BP with age is a result of changes in total

peripheral resistance and aortic compliance. Baroreceptors (stabilize BP during movement/activity)

become less sensitive with aging. This may contribute to the relatively common finding of orthostatic hypotension.

Age-related Changes In The Lung

Age-related Changes in The Lung

The number of cilia & their level of activity is reduced.

Decreased number of nerve endings in larynx.

The cough reflex is blunted thus decreasing the effectiveness of cough.

Age-related Changes in The Lung

The number of FUNCTIONAL alveoli decreases as the alveolar walls become thin, the aveoli enlarge, are less elastic.

elasticity of the lungs. The loss of elasticity accounts for "senile hyperinflation.

The respiratory muscles strength & endurance. There is increased rigidity of chest wall (ie, decreased

compliance). Osteoporosis of the vertebrae and ribs with a marked

kyphoscoliosis..

Age-related Changes in The Lung

• Since , Static &dynamic measures of lung function generally deteriorates with age for example:

– The FEV1 drops

– IRV decreased

– VC is diminished by about 20%

– RV increases by about 50%

– Sao2 decline.

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Age-related Changes in The Lung

• Combine less functional alveoli with slightly thickened capillaries decreased surface area available for O2-CO2 exchange lower O2 to supply vital organs. Which results in :

A- Less oxygen in the system cuts down the amount of work that can be done. B- Loss of efficiency in breathing especially during ex. -E.g.: elderly compliant of shortness of breathing while going upstairs.

Age-related Changes in Musculoskeletal system

• Muscles ↓ muscle strength associated with decline in major

function even ADLs. The overall age- related strength loss ranges from 24-45%.

Beginning at 30, The rate of decrease is similar for both males and females

↓ muscle mass occurs with age ↓ activity & disuse atrophy further ↓ in muscle mass and strength

Some of this muscle-wasting is due to diminished growth hormone production but exactly how much is due to aging versus disuse is unclear.

Possible mechanism of reduction in muscle mass

Aging

A loss of functioning motor neurons

Denervation of muscle fiber

Atrophy of muscle fibers

Replacement by connective tissue

decrease number of muscle fibers

Reduction in muscle mass

Age-related Changes in Musculoskeletal system

– With age, sarcopenia (↓ muscle mass & contractile force) is associated with increased fatigue & risk of falling (so may compromise ADLs).

– Sarcopenia affects all muscles including, for example,

• the respiratory muscles (↓ efficiency of breathing)

• GI tract (constipation).

– Decrease in muscle flexibility & edurance

Age-related Changes in Musculoskeletal system

• Bone/Tendons/Ligaments – Gradual loss of bone mass (bone resorption > bone

formation) starting around age 30 years.

– Decreased water content in cartilage

Decreased water in the cartilage of the intervertebral discs results in compressibility and ↓ flexibility. This may be one reason for loss of height.

– There is also some decrease in water content of tendons & ligaments contributing to ↓ mobility.

Aging Changes skin

– The skin wrinkles, looses elasticity and a decline in cell replacement occurs.

– Skin heal more slowly .

– Fat under the skin starts to get thinner and less stretchy The skin becomes thinner & tears easily.

– Vitamin D production declines.

– Skin develops spots

– Does not keep body cool in the heat due to less perspiration(sweating) with age

Questions

Q1:- Ture or false :

1- The greater number of functioning cells per

organ the greater the vitality.

2- Sarcopenia is decrease creased muscle mass & increased contractile force.

3- The skin becomes thinner & tears easily due to decrease in muscle mass under the skin .

Q2: What is the different between age related changes & pathological changes ?

Any Q?